Improvement in blackboard-rubbers



D. JACKSON.

BLACKBQARD-RUBBER.

I No.18Z,93Z. Patented Oct. 3,1876.

fa) e IZZoI' Iavid 021.0708 on.

mr/aey N PETERS PHOTO-LITHOGRAPHEP, WASHINGTON 0 C UNITED STATES PATENT QFFICE.

DAVID JACKSON, OF CHICAGO, ILLINOIS.

IMPROVEMENT IN BLACKBOARD-RUBBERS.

Specification forming part of Letters Patent No. 182,932, dated October 3, 1876; application filed March 6, 1876.

h To all whom it may concern:

Be it known that I, DAVID J AGKSON, of Chicago, in the county of (300k and State of Illinois, have invented certain new and useful Improvements in Rubbers for Blackboards, of which the following is a specification:

This invention relates to certain improvements in that class of blackboard-rubbers for erasing chalk-marks thereon, in which an endless strip of carpet or other suitable material is employed in connection with a suitable block and handle, in such manner that the position of the carpet can be readily changed, so as to present a new rubbing surface as the said carpet or other material becomes worn and it consists of an angular block of wood or other suitable material connected at each end by suitable braces with a handle of wood or other s able material, the lower side of vided with an" angular or V-shaped ecess, iiito which the carpet is adapted to be clamped by means of a detachable triangular wedge in such manner that any portion of its surface may be exposed to form the face of the rubber, substantially as hereinafter described.

In the drawing, Figure 1 represents a perspective View of my improved rubber. Fig. 2 represents an end view of the same; and Fig. 3, a detached view of the clam ping-wedge.

The letter A represents an angular block of wood or other suitable material, of suitable length, secured at each end by means of metallic braces 13 B, provided with angular spaces or openings for the insertion of the clamping-wedge, to be hereinafter described, to a handle, 0, of wood or other suitable material, provided with an' angular recess, D. E represents an endless strip of carpet or other suitable material surrounding the block A, and setting loosely over the same in such manner that it may be shifted thereon, so that any portion of its surface may be exposed under the block A to form a rubbing surface, in order to present successive portions of the carpet as it becomes worn. F represents an angular-shaped wedge, smaller at one end than at the other, which is adapted to set under the endless band of carpet or other material, and clamp it into the angular recess D on the under side of the handle, thus securing the carpet firmly in position on the block.

The operation of my invention will be readily understood from the foregoing description. In order to shift the carpet or other material which forms the endless band or strip the Wedge is removed, when the said carpet can be readily moved by hand, so as to expose any portion of its surface under the block. When the desired part is thus presented to form a rubbing surface the band or strip is secured by inserting the wedge.

What I claim, and desire to secure by Letters Patent, is-

lhe combination of the block A, fitted with the endless band of carpet or other material E, with the handles 0 connected thereto by braces B B, and provided with an angular recess on its under side, and the triangular wedge F, for clamping the band in place, substantially as described.

In testimony that I claim the foregoing I have hereunto set my hand in the presence of the subscribing witnesses.

DAVID J AOKSON.

Witnesses:

A. FELLHEIMER, J 0s. GOTTHELF. 

